Polymerizing vinylidene chloride



Patented June 6, 1939' I r I I i 2,160,936

UNITED STATES PATENT I OFFICE POLYMERIZING'VINYLIDENE CHLORIDE, John H. Reilly and Charles new, Midland, p

Mich, assignors to-The Dow Chemical Com gig, MidlanmMiclL, a corporation of Mich- 1 No Drawing. Appuoanoa. September 18,1937, 1

- Serial n mas zo- V 4 Claims. (c1. 200-49 This invention relates to the polymerization oi agents,- plasticizers, and the like, which are not Vinylidene chloride, especially to a process" wliere'i inhibitors of the. polymerization of Vinylidene by the polymer may be obtained directly as an chloride in'the' presence of a liquid of the type amorphous, powdery material suitable forus'e as mentioned may be incorporated in the mixture 5 a molding powder. prior topolymerization, if desired. When Vinylidene chloride alone is subjected to In a preferred method of carrying outthe prespolymerizing conditions, i. e., to the action or ent invention, {substantially pure monomeric light, elevated temperatures,and/or catalysta-the vinylidene'chloride is diluted with from about 1 polymeric product is ordinarily obtained as a ,to about 30 per .cent'of ortho-dichloro-benzene, rubbery or bone-like material, In-order'to fabrie by Weight. The mixture is covered with a layer cate articles from a polymer obtained in such I, 0i w'aten'which acts. as a sealing agent to'exclude state, it has ordinarily been the "practice to sub-l s a is sllqwed o stand, w t W t ut ject the polymeric product to a temperature above tation; at t mp between r mpera: the softening point thereof -so that it -may be, tureand about-90 C. until polymerization is sub- 15 worked while in a plastic state, or to comminute -stantial1y-comp1 e e, i; 6;, for a p d ranging the solid product and thereafter subject the from a few hours to one week. when the mix-' ground polymer to molding operations. The step; e is agitated. the polymerization p o e es of grinding or finely dividing a solid polymeric more rapid yh water or other covering qu d product has been only partially satisfactory.- is decanted from the mixture, which is then Vinylidene chloride, when agitated during polywarmed to vaporize the crtho dichlo'ro-benzene merization, yields a granular product, but it is substantially completely he fr pq yi not readily workable at temperatures sufliciently er ed Vinylidene chloride is recovered s t below its decomposition temperature to permit of whit ph u p d which s r adily dapt d its practical employment in molding operations. to molding Op o s and the like and which has It is desirable, however, when a thermoplastic n found to be readily molded at temperatures 25 sub t n i t b ld d toemploy th t somewhat lower than those required when formrial in a finely divided state, so as to obtain a ing s ap d a t s from a s d ody f p lym c shaped product of more uniform compos tion. Viny dene Chloride.

It i accordingly an object f th present i The following example is illustrative of the ve tl t provide a polymerization process practice of our invention, but is not to be con- 30 whereby a finely divided polymer of vinyidene t s t g the same. chloride may be produced directly. which is suitone lite! (1271 grams) of a mixture Co s sti able for employment in molding operations and Of 1163 grams of V y e e chloride and 103 the lik at mod r t t at r b l t grams of ortho-dichloro-benzene was treated with composition temperature, 38 grams (3 per cent by weight) of a plasticizer We have now found that the foregoing object s s n of p xy-p pylen oxide and covcan be attained and readily workable polymers Bred h a layer of W ter- The mixture was produced. by carrying out the polymerization of allowed to stand for about 4 days at a temperavinylidene chloride in the presence of a small t e of pp e y The W te was re- 40 amount oianon-polymerizable inert liqu d. which moved by decantation and the ortho-dichlorois immiscible with water but miscible with monobenzene was substantially completely removed meric Vinylidene chloride, examples of which are from the mixture by evaporation n a current of ortho-dichloro-benzene,trichloro-benzene,monowarm air at a temperature between about chloro-benzene.beta-beta'-dichloro-d*ethyl ether, and about C. The remaining product was a 45 acetylene tetrachloride, penta-chloroethane, and white powder which was readily molded at temthe like. If desired, the polymerization rate may peratures of approximately C. A polymeric be increased by elevating the reaction temperamass produced from the same batch of Vinylidene ture or by incorporating in the mixture to be r e s s e p oy d in h s example, but in r0 polymerized a small amount of a catalyst, such as, the absence of ortho-dichloro-benzene or a sim- 5 for example, phosphorus pentachloride, benzoyl ilar inert liquid, req molding temperatures peroxide, or mixtures of benzoyl peroxide with between and 220 C.

tetraethyl lead and a poly-halo-oxygen-contain- The amount of ortho-dichloro-benzene eming organic compound, such as hexachloro-diployed may be varied, but for convenience in re- 55 phenyl oxide. Heat-stabilizing agents, coloring moving it from the polymer, we have found that 65 the other hand, if much larger quantities (above 40-50 per cent) are employed, there is a marked tendency of the polymer to gel. This latter is also a useful procedure for some purposes, as is set forth more fully in a co-pending application of one of the present inventors, Serial Number 164,521, flied September 18, 1937.

Liquids other than ortho-dichloro-benzene which may be employed in a manner similar to that given in the example, and with comparable results, are generally non-polymerizable, waterimmiscible liquids, inert to the action of vinylidene chloride, and having boiling points above about 100 0., but with suflicient vapor pressure at that temperature to be readily removed from the polymer. Suitable examples are monochlorobenzene, trichlorobenzene, acetylene tetrachloride, pentachloroethane, dichloro-ethyl ether, etc. Some lower bofling water-immiscible liquids such as propylene chloride, trichloroethylene, ethylene chloride, trichloroethane, etc., may be similarly employed, and will yield an amorphous powdery or granular product, but are not generally as satisfactory as the solvents previously named.

The new process has among others the advantage of providing directly a polymeric product which can be molded at lower temperatures than a vinylidene chloride polymer produced in the absence of a water-immiscible inert liquid of the type herein described. Polymeric products have been obtained by our process which are moldable.

at temperatures between about 150 and 175 C. employing moderate pressures which would exert little if any plastic deformation on a polymer of vinylidene chloride produced in the absence of an inert liquid of the type described at the same molding temperature. Since lower moldingtemperatlm and pressures can be employedwlth the product of our process, thermal decomposition of the polymeric product during fabrication operations is substantially eliminated.

Other modes of applying the principle of our v1 invention may beemployed instead of the one explained, change being made as regards the process herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated step or steps be emp yed.

We therefore particularly point out and distinctly claim as our invention:

1. The process which comprises subjecting monomeric vinylidene chloride to polymerization in the presence of a relatively small amount of a non-polymerizable, water-immiscible, inert liquid which is miscible with monomeric vinylidene chloride, the vinylidene chloride being-the only polymerizable compound present, separating the so-formed granular polymer and freeing it from remaining solvent, the product being characterized by being readily moldable without decomposition.

'2. The process which comprises subjecting monomeric vinylidene chloride to polymerization in the presence of from 1 to 30 per cent of its weight of a non-polymerizable, water-immiscible, inert liquid which is miscible with monomeric vinylidene chloride, the vinylidene chloride being the only polymerizable compound present, separating the so-formed granular polymer and freeing it from remaining solvent, the product being characterized by being readily moldable without decomposition at temperatures at least 15 centigrade degrees lower than vinylidene chloride the steps which consist in polymerizing vinylidene chloride in the presence of from 1 to about 30 per cent by weight of ortho-dichloro-benzene, and thereafter removing substantially completely the ortho-dichloro-benzene.

JOHN H. REILLY. CHARLES R. RUSSELL. 

